The invention relates to a method and a device for detecting a true product jam in a folder.
Japanese Patent JP 5 26382 discloses a device for detecting a paper jam or buildup in a folder. In this heretoforeknown device from the state of the art, a sensor is disposed at a defined location in the folder along the copy transport path, and detects the presence of folded products transported along the path. When the results of the detection show that a paper jam or buildup is occurring at the aforementioned defined location, the rotary printing machine must be stopped. In the improvement in the art presented in this Japanese patent, a test mode is provided, wherein cutoff functions can be simulated, but the cutoff function which brings the rotary printing machine to a stop is blocked. It is thus possible to check whether or not a safety cutoff is functioning reliably as is required when a paper jam is detected in a folder downline of a rotary printing machine. Japanese Patent JP 5 26381 discloses a device for detecting a paper jam or buildup in a folder, wherein a sensor is likewise arranged at a defined location along the folded-copy transport path. The sensor detects the presence of copies transported along the path and, based upon the detection results, establishes that there is a paper jam at the respective location at which the sensor is integrated into the transport path of the copies. Care is taken to ensure that, when the power source is applied, different signals are emitted in a case wherein the sensor is connected to the main circuit and in a case wherein the sensor is separated from the main circuit.
Finally, Japanese Patent JP 5 26379 discloses a further device for locating a paper jam or buildup in a folder. This device is equipped with sensors which are likewise arranged at defined locations, in order to detect the presence of copies transported along the folded-copy transport path. Facilities are provided for deciding whether or not, based upon the results of detection by the sensors, there is a paper jam at the respective location. Furthermore, indicators are provided for indicating a paper jam, based upon the decision of the aforementioned decision-making facilities. The indicators include memories which maintain the indication of a paper jam and which, when a paper jam is present, cause only that location to appear on an indicator at which a paper jam was first indicated as being present by the aforementioned decision-making facilities.
In copy-processing machines, for example, a rotary printing machine with a downline folder, copy jam or buildup detection is based upon an evaluation of the number of cutting-cylinder revolutions, and an evaluation of the copies seen and correspondingly counted along the copy transport path by the sensor cells. When detached paper shreds or copy fragments move through the folder, which may be swirled around by airflows, these may falsely suggest the occurrence of a copy jam or buildup, even though no copy jam or buildup exists This may be due to the fact that the paper shreds cover a sensor cell in such a way that the sensor cell can no longer reliably count the folded copies passing per unit time. In individual instances, detached pieces of paper or paper shreds have been counted as intact copies by the sensor technology within a folder. A comparison of the counted copies with the copies actually counted off from the incoming material web by the pair of cutting cylinders has led to implausible results.
In view of the prior art outlined it is accordingly an object of the invention to provide a device for detecting a true product jam or build-up in a folder and, more particularly, sensor technology for ensuring a correct indication of a copy jam or buildup.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a method for detecting a copy jam or buildup in a folder, by sensors assigned to a copy transport path for determining a sequence of copies along the copy transport path, the sensors, respectively, being formed of a transmitting part and a receiving part, which comprises having the sensors release an input signal to a paper jam-detection device, in response to the presence of copies detected by the receiving parts of the sensors; and having the input signal produce a counting pulse.
In accordance with another mode, the method of the invention includes providing the paper jam-detection system with inverting inputs for triggering the counting pulse when there is no voltage at the receiving parts.
In accordance with a further mode, the method of the invention includes continuously sensing the edge regions of the copies with the sensors.
In accordance with an added mode, the method of the invention includes comparing the number of revolutions of a cutting-cylinder pair with the number of copies passing the sensors for determining a paper jam in the folder.
In accordance with an additional mode, the method of the invention includes failing to release a counting pulse when the input signal at the paper jam-detection device is based upon a voltage signal from only one of the receiving parts.
In accordance with a further aspect of the invention, there is provided a system for detecting a copy jam in a folder by sensors assigned to a copy transport path for detecting a sequence of copies along the copy transport path, comprising a parallel-connected arrangement of the sensors wherein the sensors are assigned to edge regions of the copies, and serve simultaneously for sensing the copy transport path.
In accordance with an added feature of the system of the invention, the sensors, respectively, include both a transmitting part and a receiving part.
In accordance with an additional feature of the system of the invention, the sensors, respectively, are connected at one voltage level and have a live voltage-carrying output.
In accordance with yet another feature of the system of the invention, the voltage-carrying outputs are combined for generating an input signal to the paper jam-detection device.
In accordance with yet a further feature of the system of the invention, the receiving parts include switching elements and identical open contact positions for generating a counting pulse at the paper jam-detection device.
In accordance with yet an added feature of the invention, at least one closed contact on the receiving parts serves for generating an input signal which does not trigger a paper jam detection.
In accordance with a concomitant aspect of the invention, there is provided a folder with a copy transport path, along which copies are transported in a continuous sequence, and sensors assigned to the copy transport path, the sensors, respectively, including a transmitting and a receiving part, comprising at least one parallel-connected sensor pair arrangement provided along the copy transport path for sensing the copy transport path simultaneously with producing combinable output signals by the receiving parts of the sensor-pair arrangement.
Thus, by the further developments proposed in accordance with the invention, in the detection of a paper jam or buildup, a counting pulse is triggered only when both sensors indicate the presence of a folded or foldable copy to be transported. Paper shreds or detached product fragments are detected as such and, when they enter the field of detection of one of the sensors, do not generate a counting pulse in the paper jam or buildup detection-device. There is therefore no false indication of a paper jam or buildup; if one of the sensors of a sensor pair fails, the rotary printing machine can nevertheless continue to operate with minimal wiring changes, and the paper jam or buildup-detection device continues to be active.
If the paper jam or buildup-detection device has inverting inputs in order to increase redundancy, a counting pulse is triggered in the paper jam or buildup-detection device whenever there is no voltage at the receiving parts of the sensors of the sensor pair. In this case, both sensors of the respective pair see a folded or foldable copy, and this is detected as such and is counted correspondingly. The sensor pairs are oriented along the copy transport path in a manner that they preferably detect edge regions of the folded or foldable copies conveyed in rapid sequence and are arranged eccentrically with respect to the copy transport path. In order to detect a copy jam or buildup, the paper jam or buildup-detection device continuously compares the numbers of revolutions of the cutting-cylinder pair with the number of counted copies.
The sensors, respectively, include a transmitting and a receiving part. Radiation is emitted continuously from the transmitting part to the receiving part, and the two sensors of the sensor pair are connected in parallel. The sensors are at one voltage level and include electric contact elements which, when both sensors detect folded or foldable copies, remain open and trigger a counting pulse on the paper jam or buildup-detection device by inverted inputs thereat. Where a contact of one of the sensors of the sensor pair is closed, no counting pulse is generated, and the paper jam or buildup-detection device remains inactive.
The method according to the invention can be employed in folders both for newsprinting and for job printing, whether on folders with sets of pins or on folders operating without pins.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and device for detecting a true product jam or buildup in a folder, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.